This card is ideal for Rock defense decks, as rocks are generally EARTH attribute, with low ATK and high DEF, although "Chorus of Sanctuary" is a better choice.
However, the ATK decreasing effect of this card will prove useful if the opponent uses EARTH monsters to attack, as long as you use yours only to defend. As an example, an opponent's "Goyo Guardian" would be unable to defeat any of your 1900 or more DEF monsters.
In a Stall Deck, use this card with "DNA Transplant". By selecting EARTH, your opponent will have to overcome an additional 900 difference between your monsters and theirs: 500 Attack lost on their monsters while yours gain 400 more Defense.